The aims of our study were to examine some effects of clothing colours on thermophysiological responses and endurance of handgrip exercise under the warm conditions with the artificial and natural sun radiation. Black and white garments made of cotton were consisted of T-shirts with long sleeves and long trousers.
　In the first experiment, 7 subjects volunteered and kept sitting for 1 hour in the chamber at 32°C with the artificial sun radiation. The main results were as follows; though rectal temperature was kept constant revel between black and white garment during the experiment, skin temperature on foot, local sweat rates from forearms and mass loss were higher in the white garment. Clothing surface temperature was significantly higher level in the black.
　In the second experiment, 1 subject sat for 1 hour under the outdoor conditions in summer in Nara. After then, handgrip exercise was per-formed until volitional exhaustion and the number of contractions was counted. Major findings were that clothing surface temperature in the black increased higher than that in the first experiment and the number of contractions was greater in the black garment after 1 hour sitting in the sun.
　This study presented that thermoregulatory effectors were activated more and the endurance to handgrip exercise was smaller in the white garment under the summer sun radiation.

DESCENTE SPORTS SCIENCE Vol.18/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE